This application is based on application No. 2002-55196 filed in Japan, contents of which are hereby incorporated by reference.
1. Field of the Invention
The present invention relates to a color image forming apparatus such as a color copying machine or a color printer used to obtain color images, and more particularly to a color image forming apparatus in which multiple developing devices that house toners of various colors are held by support members that are disposed at prescribed locations on a rotatable support unit, and which performs development by rotating the rotatable support unit to sequentially lead each developing device to a position facing an image carrier.
2. Description of the Related Art
Color image forming apparatuses such as color copying machines and color printers that obtain color images using multiple developing devices housing toners of different colors have been in use in recent years.
As one such color image forming apparatus, an apparatus has been in use in which four developing devices 10a-10d, each of which houses a toner of a different color, are held by prescribed support members 21a-21d on a rotatable support unit 20, the rotatable support unit 20 is rotated to sequentially lead each developing device 10a-10d to a position facing an image carrier P, and the different color toners are sequentially supplied to the image carrier P from the toner carriers 11a-11d of the developing devices 10a-10d to develop a full-color image, as shown in FIG. 1.
The color image forming apparatus described above gives rise to the problem, however, that unless the developing devices 10a-10d are held by the prescribed support members 21a-21d, respectively, on the rotatable support unit 20, toner of the wrong color is supplied to the image carrier P, resulting in a failure to obtain an image having the desired coloring.
Therefore, in the conventional art, as shown in FIG. 1 referred to above, for example, verification protrusions 23a-23d are disposed on a partition member 22 that separates the support members 21a-21d on the rotatable support unit 20 such that the positions of the verification protrusions differ for each support member 21a-21d, and verification concavities 12a-12d are disposed in the developing devices 10a-10d such that the verification concavities 12a-12d correspond to the verification protrusions 23a-23d on the support members 21a-21d, respectively, so that each developing device 10a-10d can be held by a prescribed support member 21a-21d of the rotatable support unit 20 by engaging the verification protrusion 23a-23d of the support member 21a-21d with the verification concavity 12a-12d of the developing device 10a-10d.
However, manufacturing must be carried out using molds corresponding to each of the developing devices 10a-10d in order to ensure that verification concavities 12a-12d are disposed at different locations on the developing devices 10a-10d, which leads to a higher manufacturing cost, and the developing devices 10a-10d cannot be used for any other colors but the originally designated toner color, resulting in a lack of versatility.
In addition, because verification concavities 12a-12d are disposed in the developing devices 10a-10d as described above, the volume of the interior of each developing device 10a-10d decreases, reducing the amount of toner in each developing device 10a-10d.
An object of the present invention is to resolve the problems identified above in a color image forming apparatus in which multiple developing devices housing toners of different colors are held by support members that are disposed at prescribed locations on a rotatable support unit, and which performs development by rotating the rotatable support unit to sequentially lead each developing device to a position facing an image carrier. rotatable support unit to sequentially lead each developing device to a position facing an image carrier.
In other words, an object of the present invention is, in the color image forming apparatus described above, to have the developing devices easily held by prescribed support members on the rotatable support unit while using developing devices having the same configuration, without the need to dispose a verification concavity in each developing device at a different location for each developing device as in the conventional art, resulting in a lower manufacturing cost and increased versatility for each developing device, as well as in eliminating the reduction in the interior volume of each developing device, enabling a sufficient amount of toner to be housed in each developing device.
In order to attain the above object, the color image forming apparatus pertaining to the present invention comprises a color image forming apparatus in which multiple developing devices housing toners of different colors are held by support members disposed at prescribed locations on a rotatable support unit, and which performs development by rotating the rotatable support unit to sequentially lead each developing device to a position facing an image carrier, wherein a guide member is mounted to one side end of each developing device, and engaging members of different configurations are disposed in each guide member such that each of the multiple developing devices is held by a support member at a prescribed location on the rotatable support unit through engagement of the engaging members of the guide members mounted to adjacent developing devices.
Where a guide member is mounted to one side end of each developing device, and engaging members having different configurations are disposed in each guide member such that the engaging members of the guide members mounted to adjacent developing devices are made to engage with each other, as in the color image forming apparatus of the present invention, if during placement of the developing devices on the support members of the rotatable support unit a developing device is placed on the support member at a wrong location, the engaging members of the guide member mounted to the developing device do not engage with the engaging members of the guide members mounted to the adjacent developing devices, and as a result the developing device is prevented from being placed on the support member at a wrong location.
In addition, in the color image forming apparatus of the present invention, because a verification concavity need not be disposed in each developing device such that the verification concavity in each developing device is disposed at a different location for each developing device as in the conventional art, the interior volume of the developing devices does not decrease, enabling each developing device to house a sufficient amount of toner, and at the same time, because developing devices of the same configuration can be used, the developing device manufacturing cost can be reduced, and a toner different from the original toner can be housed in a given developing device, thereby increasing the versatility of the developing device.
In the color image forming apparatus of the present invention, when the multiple developing devices are placed on support members at prescribed locations on the rotatable support unit, one developing device is first placed on a support member at a prescribed location on the rotatable support unit, and subsequently the other developing devices are placed on the support members at prescribed locations on the rotatable support unit by engaging the engaging members of the guide members mounted to the developing devices, as described above.
It is preferred that a positioning member that enables at least one developing device to be placed on its corresponding support member on the rotatable support unit be included in order to ensure that the first developing device is placed on the support member at a prescribed location on the rotatable support unit without error.
The above problems are also resolved by a color image forming apparatus in which multiple developing devices housing toners of different colors are held by support members at prescribed locations on a rotatable support unit, and which performs development by rotating the rotatable support unit to sequentially lead each developing device to a position facing an image carrier, wherein such apparatus includes guide members mounted to one side end of each developing device, as well as a first engaging member disposed in the guide member mounted to a first developing device, a second engaging member that is mounted to a second developing device adjacent to the first developing device and can engage with the first engaging member, a third engaging member that is disposed in the guide member mounted to the second developing device and has a different configuration from the first and second engaging members, a fourth engaging member that is mounted to a third developing device adjacent to the second developing device and can engage with the third engaging member, and support members that hold the multiple developing devices at prescribed locations on the rotatable support unit through the engagement of the first and second engaging members and the third and fourth engaging members.
Furthermore, the above problems are also resolved by a color image forming apparatus in which four developing devices, i.e., first through fourth developing devices, which house toners of different colors, are held by support members at prescribed locations on a rotatable support unit, and which performs development by rotating the rotatable support unit to sequentially lead each developing device to a position facing an image carrier, wherein such apparatus includes guide members mounted to one side end of each of the developing devices, a first engaging member that is disposed in the guide member mounted to the first developing device, a second engaging member that is disposed in the guide member mounted to the second developing device adjacent to the first developing device and can engage with the first engaging member, a third engaging member that is disposed in the guide member mounted to the second developing device and that has a different configuration from the first and second engaging members, a fourth engaging member that is disposed in the guide member mounted to the third developing device adjacent to the second developing device and can engage with the third engaging member, a fifth engaging member that is disposed in the guide member mounted to the third developing device and that has a different configuration from the first through fourth engaging members, a sixth engaging member that is disposed in the guide member mounted to the fourth developing device adjacent to the third developing device and can engage with the fifth engaging member, a seventh engaging member that is disposed in the guide member mounted to the fourth developing device and that has a different configuration from the first through sixth engaging members, an eighth engaging member that is disposed in the guide member mounted to the first developing device adjacent to the fourth developing device and can engage with the seventh engaging member, and support members that hold the four developing devices at prescribed locations on the rotatable support unit through the engagement of the first and second engaging members, the third and fourth engaging members, the fifth and sixth engaging members and the seventh and eighth engaging members.
In addition, the above problems are also resolved by a method for manufacturing developing devices used in a color image forming apparatus in which guide members are mounted to one side end of each of multiple developing devices housing toners of different colors, engaging members having different configurations are disposed in the guide members, each developing device is held by a support member at a prescribed location on a rotatable support unit through the engagement of the engaging members of the guide members mounted to adjacent developing devices, and development is performed by sequentially leading each developing device to a position facing an image carrier through rotation of the rotatable support unit, such apparatus being manufactured by placing a toner of a prescribed color in a toner holder of each developing device and mounting a guide member having engaging members for that color to a prescribed area of the developing device.
By virtue of this construction, the developing device may be used for any color regardless of the color of the toner that was originally placed in the developing device, enabling easy recycling.
In the color image forming apparatus of the present invention having the above construction, because a guide member is mounted to one side end of each developing device and engaging members of different configurations are disposed in each guide member such that the engaging members of the guide members mounted to adjacent developing devices can be made to engage together when the multiple developing devices housing toners of different colors are placed on the support members at prescribed positions on the rotatable support unit, the engaging members of the guide member mounted to a developing device do not engage with the engaging members of the guide members mounted to the adjacent developing devices if the developing device is placed on a support member at an incorrect location. Consequently, the developing device is prevented from being placed on a support member at an incorrect location, and the developing devices are reliably placed on the support members at the prescribed locations on the rotational support unit.
In addition, in the color image forming apparatus of the present invention, because a verification concavity need not be disposed in each developing device such that the verification concavity in each developing device is at a different location for each developing device, as in the conventional art, the interior volume of the developing devices does not decrease and therefore each developing device can house a sufficient amount of toner, and at the same time, because developing devices having a uniform configuration can be used, the developing device manufacturing cost can be reduced, and toner different from the original toner may be housed in a given developing device, which increases the versatility of the developing device.
These and other objects, advantages and features of the invention will become apparent from the following description thereof taken in conjunction with the accompanying drawings which illustrate specific embodiments of the invention.